What are the causes of delayed seroconversion

AIDS (Acquired Immune Deficiency Syndrome)

AIDS is the abbreviation for Acquired Immune Deficiency Syndrome. AIDS is a viral infection caused by the HI virus (HIV = human immunodeficiency virus). However, one speaks of AIDS only when the symptoms of the immune deficiency have reached severe proportions (see below). Diseases that are particularly characteristic of AIDS are referred to as Adi (AIDS defining illnesses).

The genome (genome analysis) of the HI virus consists of RNA, which after penetrating the human cell is converted into DNA by an enzyme, the retrotranscriptase. Since the conversion of RNA into DNA is a reversal of the normal process, viruses of this type are referred to as retroviruses (retro = reversed). The virus DNA formed in this way is incorporated into the DNA of the cell and thus belongs to the cellular genome of the host cell. The body is not able to distinguish the viral DNA from its own DNA, but it now carries out the production of new viruses itself.

Mutations (changes in the genetic code) often occur during the replication of the HI virus. As a result, many different types of HIV (quasi-species) are created. The formation of specific antibodies cannot keep pace with the rapid changes in the antigen structures. Prevention through vaccinations has also failed due to the mutation problem.

Initially, the HIV virus is latent in the body, and in this early phase an infection can only be detected with special tests. In the course of a few weeks to months, antibodies are then formed (seroconversion), which can be detected in a laboratory using appropriate tests (ELISA search test, Western blot confirmation test). With more recent methods, the HIV genome can be detected as viral RNA or DNA, so that the diagnosis can be made with greater certainty and at an earlier point in time.

During seroconversion, an acute febrile clinical picture usually occurs for a few days to weeks with very different symptoms such as tiredness, rash, headache, confusion, mild liver inflammation, etc. After that, the HIV infection remains hidden for a long time (latency phase ). Subjectively, there is initially nothing to suggest that the infected person is contagious, but it is becoming increasingly infectious. Enlarged lymph nodes can only be found in some of those who are HIV-positive. Since this is not painful, it is usually not noticed.

The period between infection and clear physical symptoms is an average of six to ten years. This also depends on how the infection took place and how strong the constitution of the infected person is.

The HIV virus primarily attacks the cells of the immune system, especially the CD4 lymphocytes (T4 lymphocytes, helper cells). Almost all symptoms of illness can essentially be explained by the progressive impairment of the immune system. Although the person concerned does not feel anything at first, the immune system is increasingly destroyed during the latency phase. The number of helper cells decreases and there are various infections such as shingles (herpes zoster), herpes simplex, oral thrush (fungal disease of the oral mucosa) or non-specific symptoms such as diarrhea, weight loss and fever. The patients feel weak and generally poor in performance. Another problem of the inadequate immune response is the likelihood of malignant tumors.

As the helper cells continue to sink, the AIDS disease finally develops after another two to three years. Pathogens, which in healthy people can normally be blocked by their own defenses or at least with the help of medication, lead to severe infections (so-called opportunistic infections) in AIDS patients and often have fatal consequences. The most common are pneumonia, tuberculosis, salmonella or cytomegalovirus infections. The central nervous system can also be directly affected with ascending paralysis.

Transmission:

HIV infection is transmitted through body fluids such as blood, semen, or vaginal secretions. Typical routes of infection are sexual transmission, the use of infected hypodermic needles and transmission in the womb. Due to strict controls, new infections through transfusions of blood or blood products no longer play a role.

The risk group with the highest HIV / AIDS risk in Germany is still homosexuals (63%) (source: Robert Koch Institute). This is followed by drug users, people from countries of origin with a high prevalence and heterosexually infected people with around 12% each. Mother-to-child transmission is the cause of <1% of HIV infections. In developing countries, heterosexual transmission is at the top with 70%.

Compared to other pathogens (e.g. hepatitis B virus), the HI virus is significantly less infectious. The highest risk of transmission is with direct blood transmission of HIV-infected blood (> 90%), with maternofetal transmission it is 20%, with sexual intercourse between 0.5 and 10%, depending on the population, with a single puncture injury with an infected cannula around 0.4%. HI viruses are also found in saliva and tears, but infection from this is extremely unlikely.

AIDS at work:

For those infected with HIV and AIDS sufferers, social exclusion poses a major problem. Especially those patients who are in the latency phase or who are being treated successfully and who are likely to be able to perform unimpaired for years to come, will confess Their infection is mostly made impossible by fear of losing their jobs. At least they firmly expect to be isolated in the workplace and eventually forced out of the company.

However, the fear of HIV infection from work colleagues is usually unfounded, as normal human contact cannot lead to an HIV infection. Transmission via the intact skin can be ruled out with a probability bordering on certainty. An HIV infection therefore does not normally constitute a reason for dismissal or an occupational ban. An exception are medical professions in the surgical area, which can endanger the patient through personal injuries.

On the other hand, there is an increased risk of HIV infection from infected patients for medical personnel due to their work. Stab and cut injuries with HIV-contaminated instruments and the transmission of HIV-infected blood to injured or damaged skin or mucous membranes are important transmission routes. If an injury has occurred, prophylactic measures should be taken immediately to prevent the infection from being attacked if a risk of HIV infection is suspected. The pathogen's entry point must be disinfected immediately. Puncture / cut injuries should be allowed to bleed out beforehand by applying pressure to the surrounding tissue. Antiretroviral therapy should then be initiated within two hours. As a rule, compliance with the hygiene regulations (hygiene), as z. B. were set up to protect against hepatitis B infections, largely avoid HIV infections in the medical staff.

Therapy:

Since the introduction of highly active antiretroviral therapy (HAART), which is a combination of various drugs, the course of the disease in HIV patients has improved significantly, mainly in industrialized countries, as the virus replication can be slowed down and the outbreak of AIDS can be delayed. For the patient, drug therapy is a burden, which often leads to the fact that the intake instructions are not adhered to or cannot be adhered to at all in developing countries. On the African continent, only around 0.1% of those infected receive antiretroviral therapy.

Distribution:

A stabilization of the new HIV infection rate is becoming apparent, especially in the industrialized countries. Preventive measures such as the use of condoms, methadone substitution, and stricter control of blood donors have shown clear success. Since the beginning of the HIV epidemic, around 75,000 people have been infected in Germany, around 26,000 of whom have died. There are currently around 49,000 HIV-infected people in Germany. About 80% of those infected are men, 19% women, <1% children. The new infection rate is 2,600 per year. Aids disease has broken out in around 8,000 people. Around 850 AIDS patients are added each year, and around 750 die.

Compared to the partial successes in the industrialized nations, the AIDS statistics of the world population are frightening. UNAIDS (UN Aid Organization to Fight AIDS) estimates that around 40.3 million people worldwide are currently infected with the HI virus (20.5 million men, 17.5 million women, 2.3 million children under 15 years). In 2005 over 3.1 million people died of AIDS; the number of new infections in 2005 is given as 4.9 million. The explosive spread of AIDS in some countries in Africa, Asia and recently also in Eastern Europe, combined with inadequate preventive measures and a lack of resources to finance medical treatment, suggests a catastrophe of unimagined proportions in the near future.

NOTE: Some of the information in this text is a bit out of date and is currently being revised. (Date: October 15, 2019)

literature

  • Law for the prevention and control of infectious diseases in humans (Infection Protection Act - IfSG)
  • Biological agents in health care and welfare work (also as TRBA 250) (BGR 250)
  • AIDS, leaflet for those insured in the health service, rescue and medical service (GUV 28.14)
  • Bengel, J./Leisz, G./Röhr, B .: Psychosocial stress caused by fear of HIV infection in medical staff. In: Occupational Medicine - Social Medicine - Preventive Medicine 27, 1992, pp. 14-17
  • Hirschel, B .: AIDS, Hans Huber Verlag, Bern 1995
  • Robert Koch Institute
  • UNAIDS - Joint United Nations Program on HIV / AIDS

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